In laying underground cable and electrical wires, a bore hole is drilled and lined with piping to form a conduit. Cables or electrical wires are then run through the pipe. The pipe provides protection against water, dirt, cuts, compression, and the like.
One type of piping system employs HDPE pipe that is stored on and dispensed from a reel. This system suffers from a number of drawbacks, including problems with handling the reel, fusion welding of pipe connections, uncoiling of pipe, wasted pipe, safety hazards and increased labor costs.
One preferred piping system employs a plurality of sections of PVC pipe. The sections of pipe are preferably between 10 to 20 feet in length, so that they are easy to ship and handle. The pipes have inner diameters ranging from about 3 to 6 inches, depending on the application. The sections of PVC pipe are fastened end-to-end so as to prevent water, dirt and the like from entering the pipe. An o-ring or gasket is used to form a water-tight seal between adjacent pipes. Once the pipes are in place, a plurality of cables and/or wires are run through the pipes.
Connecting the pipes end-to-end presents various problems. The pipes can be glued together, but this process is time consuming, and therefore expensive. Additionally, glued joints are not strong enough for boring. Accordingly, attempts have been made to develop alternative coupling systems.
Several companies, including include Carlon/Lamson & Sessions, Certainteed, and Victaulic, distribute a pipe coupling system that employs a nylon locking strap. The strap has a locking means on opposing ends thereof. An annular groove is formed on an inner surface of a receiving end of a first pipe. An aperture extends through the wall of the pipe and communicates with the groove. A matching groove is formed on an outer surface of an insertion end of a second pipe. The insertion end of the second pipe is inserted into the receiving end of the first pipe until the groove and the matching groove are opposite one another. Once the grooves are lined up, the strap is inserted into the aperture and slid into the opposing grooves. The strap is sized to occupy both the groove and the matching groove, such that the strap and the grooves together prevent the first and second pipes from sliding relative to one another. While the strap mechanism is effective for locking pipes end-to-end, it can be difficult to align the opposing grooves and to insert the strap into the opposing grooves. The separate straps also require installation by the end user, which increases installation cost. Additionally, straps may become dislodged during pipe installation, resulting in uncoupling of pipes.
There is thus a need for a pipe coupling system having the following characteristics and advantages over the prior art.